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# /***********************************************
# * *
# * Jeff Molofee's Revised OpenGL Basecode *
# * Huge Thanks To Maxwell Sayles & Peter Puck *
# * http://nehe.gamedev.net *
# * 2001 *
# * Adapted to PyOpenGL GLUT *
# * *
# ***********************************************/
#
# NeHe Tutorial Lesson: 48 - ArcBall Rotation
#
# C version of tutorial by Terence J. Grant
# This code was created by Jeff Molofee 2000
# Ported to PyOpenGL 2.0 by Brian Leair 2004
#
# The port was based on the PyOpenGL tutorials and from
# PyOpenGLContext (tests/glprint.py)
#
# If you've found this code useful, feel free to let me know
# at (Brian Leair telcom_sage@yahoo.com).
#
# See original source and C based tutorial at http://nehe.gamedev.net
#
# Note:
# -----
# This code is not an ideal example of Pythonic coding or use of OO
# techniques. It is a simple and direct exposition of how to use the
# Open GL API in Python via the PyOpenGL package. It also uses GLUT,
# a high quality platform independent library. Due to using these APIs,
# this code is more like a C program using procedural programming.
#
# To run this example you will need:
# Python - www.python.org (v 2.3 as of 1/2004)
# PyOpenGL - pyopengl.sourceforge.net (v 2.0.1.07 as of 1/2004)
# Numeric Python - (v.22 of "numpy" as of 1/2004) numpy.sourceforge.net
#
#
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import sys
from Lesson48 import * # Draw (), Initialize () and all the real OpenGL work.
from ArcBall import * # // *NEW* ArcBall header
# *********************** Globals ***********************
# Python 2.2 defines these directly
try:
True
except NameError:
True = 1==1
False = 1==0
# Some api in the chain is translating the keystrokes to this octal string
# so instead of saying: ESCAPE = 27, we use the following.
ESCAPE = '\033'
# Number of the glut window.
window = 0
# A general OpenGL initialization function. Sets all of the initial parameters.
def InitGL(Width, Height): # We call this right after our OpenGL window is created.
glShadeModel(GL_SMOOTH) # Enables Smooth Color Shading
glClearColor(0.0, 0.0, 0.0, 0.5) # This Will Clear The Background Color To Black
glClearDepth(1.0) # Enables Clearing Of The Depth Buffer
glEnable(GL_DEPTH_TEST) # Enables Depth Testing
glDepthFunc(GL_LEQUAL) # The Type Of Depth Test To Do
glHint (GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST) # Really Nice Perspective Calculations
return True # // Initialization Went OK
# Reshape The Window When It's Moved Or Resized
def ReSizeGLScene(Width, Height):
if Height == 0: # Prevent A Divide By Zero If The Window Is Too Small
Height = 1
glViewport(0, 0, Width, Height) # Reset The Current Viewport And Perspective Transformation
glMatrixMode(GL_PROJECTION) # // Select The Projection Matrix
glLoadIdentity() # // Reset The Projection Matrix
# // field of view, aspect ratio, near and far
# This will squash and stretch our objects as the window is resized.
# Note that the near clip plane is 1 (hither) and the far plane is 1000 (yon)
gluPerspective(45.0, float(Width)/float(Height), 1, 100.0)
glMatrixMode (GL_MODELVIEW); # // Select The Modelview Matrix
glLoadIdentity (); # // Reset The Modelview Matrix
g_ArcBall.setBounds (Width, Height) # //*NEW* Update mouse bounds for arcball
return
# The function called whenever a key is pressed. Note the use of Python tuples to pass in: (key, x, y)
def keyPressed(*args):
global g_quadratic
# If escape is pressed, kill everything.
key = args [0]
if key == ESCAPE:
gluDeleteQuadric (g_quadratic)
sys.exit ()
def main():
global window
# pass arguments to init
glutInit(sys.argv)
# Select type of Display mode:
# Double buffer
# RGBA color
# Alpha components supported
# Depth buffer
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
# get a 640 x 480 window
glutInitWindowSize(640, 480)
# the window starts at the upper left corner of the screen
glutInitWindowPosition(0, 0)
# Okay, like the C version we retain the window id to use when closing, but for those of you new
# to Python, remember this assignment would make the variable local and not global
# if it weren't for the global declaration at the start of main.
window = glutCreateWindow("Lesson 48: NeHe ArcBall Rotation Tutorial")
# Register the drawing function with glut, BUT in Python land, at least using PyOpenGL, we need to
# set the function pointer and invoke a function to actually register the callback, otherwise it
# would be very much like the C version of the code.
glutDisplayFunc(Draw)
# Uncomment this line to get full screen.
#glutFullScreen()
# When we are doing nothing, redraw the scene.
glutIdleFunc(Draw)
# Register the function called when our window is resized.
glutReshapeFunc(ReSizeGLScene)
# Register the function called when the keyboard is pressed.
glutKeyboardFunc(keyPressed)
# GLUT When mouse buttons are clicked in window
glutMouseFunc (Upon_Click)
# GLUT When the mouse mvoes
glutMotionFunc (Upon_Drag)
# We've told Glut the type of window we want, and we've told glut about
# various functions that we want invoked (idle, resizing, keyboard events).
# Glut has done the hard work of building up thw windows DC context and
# tying in a rendering context, so we are ready to start making immediate mode
# GL calls.
# Call to perform inital GL setup (the clear colors, enabling modes
Initialize (640, 480)
# Start Event Processing Engine
glutMainLoop()
# Print message to console, and kick off the main to get it rolling.
if __name__ == "__main__":
print "Hit ESC key to quit."
main()
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